Longman Dictionary of Contemporary English
picture window
noun
EXAMPLES FROM CORPUS
▪ Although it is July, the house has a Christmas wreath hung in its picture window.
▪ He was standing in the dark, in front of a picture window, fireworks exploding silently behind him.
▪ Next door, where Ed Preston lived, somebody is watching me from the picture window.
▪ Some one looking through the picture window spotted Lois before she got more than half way up the front walk.
WordNet
picture window
n. a large window with a single pane (usually overlooking a view)